1. Field of the Invention
This invention relates to a tape useful as a sealant and for insulation. More particularly, it relates to a tape useful for repairing defective seals in secondary batteries.
2. Description of the Prior Art
Casings for secondary batteries consist of containers and covers. Usually the containers and covers are molded of a thermoplastic material such as polystyrene, polymethacrylate, polyamide, polyolefin, polyvinyl chloride, polyformaldehyde and the like. After the battery is assembled, the space between the container and cover is sealed with a sealant compound.
Most sealant compounds are not entirely satisfactory because they are not able to provide a crackfree seal during the total useful life of the battery. This is particularly true for secondary batteries exposed to vibration, very low or very high temperatures and used for applications requiring a rugged long life device. Over the course of years the sealant compound may, for a variety of reasons, become brittle and often breaks, forming cracks and holes which allow solvent to evaporate and electrolyte to escape. For such batteries to remain useful the holes and cracks, i.e., the defective seal, must be repaired.
The known compounds used for repairing defective seals are utilized in processes that require the battery to be disconnected, removed from operation, and possibly moved to a different site for the repair to be done safely. The tape of this invention can be used in a process done with complete safety while the battery is in operation and on-site.